Mechanochemical processing and microstructural characterization of pure Fe2B nanocrystals

The results of current investigation demonstrate that mechanochemical processing can be used to synthesize high purity Fe₂B nanocrystals by selecting well-optimized milling conditions, reaction paths and proper starting materials. Microstructure, phase analyses, specific surface area, and magnetic properties of the synthesized nanocrystals were examined by using X-ray diffraction/spectroscopy, electron microscopy, nitrogen adsorption–desorption methods following Brunauer-Emmett-Teller equation and vibrating sample magnetometer techniques, respectively. Removal of MgO impurity phase by leaching the resulting powder in the acetic acid solution yielded single phase Fe₂B nanocrystals with the crystallite size and specific surface area of 12.5 nm and 29 m²/g, respectively. Magnetization results clearly indicated the ferromagnetic behavior of Fe₂B nanocrystals with saturation magnetization observed around 96.26 emu·g^?1. Electron microscope images revealed coaxial/spherical powder shape and morphology of the single-phase Fe₂B nanocrystals.     

Effects of waste material–lime additive mixtures on mechanical properties of granular soils

Granular soil was stabilized using different proportions of silica fume–lime and fly ash–lime and compacted at optimum water content. Compaction, compressive strength and California Bearing Ratio tests were undertaken which confirmed that the use of waste materials and lime mixtures improved the strength properties of the crushed granular soils.     

Effect of microwave‐assisted extraction on the release of polyphenols from ginger (Zingiber officinale)

The significance of different variables viz. temperature, time and solvent at constant power in microwave‐assisted extraction (MAE) process of ginger was studied and compared with conventional method. Aqueous ethanol (50%) provided higher yields of extract as well as the highest release of total polyphenols (TPP) than alcoholic solvents. The reason could be the high dielectric constant of aqueous ethanol as compared to alcohols. Microwave heating being a volumetric process, an exposure time of 1 min was found to be sufficient. The better penetration of microwaves and greater solubility at higher temperature resulted in higher yield of TPP and [6]‐gingerol. The resultant extract showed higher radical scavenging activity (RSA) values. Thus, MAE allowed higher recoveries compared to conventional extraction process, with improvement in the quantity and quality of extract in very short period of time.     

In‐situ polymerization of polyamide 66 nanocomposites utilizing interfacial polycondensation,Part 1: Organoclay nanocomposites

Effective dispersion of organically modified montmorillonite‐layered silicates in nylon 66 is addressed by synthesizing nanocomposites in situ via interfacial polycondensation from a suspension of silicate platelets in one of the monomer phases using either a stirred or unstirred reactor, while avoiding the detrimental heat history associated with melt compounding of this high melting polymer system. The effects of mixing methodology, reaction conditions, concentration ratio, and clay content are evaluated to elucidate process mechanisms and produce high molecular weight product. Enhanced stiffness of the nanocomposites measured by tensile modulus is related to their nanoscale morphology as characterized by transmission electron microscopy and wide angle X‐ray diffraction. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers     

Effects of Fining Agents on Antioxidant Capacity of Red Wines

The antioxidant capacity of wine depends not only on the grape variety but also on the wine processing steps. The aim of this study was to determine the effects of different fining agents, used at different concentrations, on the antioxidant status of fined wines. The results demonstrated that the use of a combination of gelatin and Kieselsol led to the highest total phenol value (3,491 mg/L GAE) and antioxidant activities (29%) among the tested fining agents. Wines were mostly negatively affected by the use of egg white as an agent and led to the lowest value of total phenol (3,038 mg/L GAE) and the lowest rate of antioxidant activity (26%). Significant differences (p<0.05) were determined between gelatin, egg white, and the control groups. The results of the grouping of analyzed parameters in n‐dimensional space, with different fining agents at different concentrations, demonstrated the importance of a low concentration of fining agents for high antioxidant activity and total phenols.     

Effects of silica fume on the geotechnical properties of fine-grained soils exposed to freeze and thaw

Both the landfill liner and cover systems are the most important parts on a waste disposal landfill site. These systems are generally constructed using compacted fine-grained soils. It is known that the strength and permeability are particularly affected by freezing and thawing cycles in the cold regions. The aim of this study is to reduce the effects of freezing and thawing cycles on the strength and permeability. To modify the fine-grained soils, silica fume generated during silicon metal production as very fine dust of silica from a blast furnace and historically considered a waste product has been used as a stabilizer. The natural fine-grained soils and soil–silica fume mixtures have been compacted at the optimum moisture content and subjected to the laboratory tests. The test results show that the stabilized fine-grained soil samples containing silica fume exhibit high resistance to the freezing and thawing effects as compared to natural fine-grained soil samples. The silica fume decreases the effects of freezing and thawing cycles on the unconfined compressive strength and permeability. We have concluded that silica fume can be successfully used to reduce the effects of freezing and thawing cycles on the strength and permeability in landfill liner and cover systems constructed from compacted fine-grained soils.     

Emerging Trends in Microwave Processing of Spices and Herbs

Today, spices are integral part of our food as they provide sensory attributes such as aroma, color, flavour and taste to food. Further their antimicrobial, antioxidant, pharmaceutical and nutritional properties are also well known. Since spices are seasonal so their availability can be extended year round by adopting different preservation techniques. Drying and extraction are most important methods for preservation and value addition to spices. There are different techniques for drying of spices with their own advantages and limitations. A novel, non-conventional technique for drying of spices is use of microwave radiation. This technique proved to be very rapid, and also provide a good quality product. Similarly, there are a number of non-conventional extraction methods in use that are all, in principle, solid–liquid extractions but which introduce some form of additional energy to the process in order to facilitate the transfer of analytes from sample to solvent. This paper reviews latest advances in the use of microwave energy for drying of spices and herbs. Also, the review describes the potential application of microwave energy for extraction of essential oil/bioactive components from spices and herbs and the advantages of microwave-assisted process over the other extraction processes generally employed for extraction. It also showcases some recent research results on microwave drying/extraction from spices and herbs.